The Richardson constant and barrier inhomogeneity at Au/Si3N4/n-Si (MIS) Schottky diodes


PHYSICA SCRIPTA, vol.88, no.1, 2013 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 88 Issue: 1
  • Publication Date: 2013
  • Doi Number: 10.1088/0031-8949/88/01/015801
  • Title of Journal : PHYSICA SCRIPTA


Si3N4 films were deposited on n-type silicon substrate by the radio frequency magnetron sputtering technique. The current-voltage (I-V) characteristics of Au/Si3N4/n-Si (metal-insulator-semiconductor) Schottky diodes were investigated in the temperature range of 160-400 K. Experimental results show an abnormal increase in the zero-bias barrier height (BH) (Phi(Bo)) and a decrease in the ideality factor (n) with increasing temperature. This behavior is attributed to barrier inhomogeneities by assuming a Gaussian distribution (GD) of BHs. The conventional Richardson plot (ln(I-o/T-2) versus 1000/T) exhibits a linearity above about 300 K. The values of activation energy (E-a) and Richardson constant (A*) were found to be 0.350 eV and 1.242 x 10(-3) A cm(-2) K-2 from the slope and the intercept at the ordinate of the linear region of this plot, respectively. Also, we attempted to draw a Phi(Bo) versus q/2kT plot to determine evidence of the GD of BHs, and the values of (Phi(Bo)) over bar = 0.999 eV and sigma(s) = 0.137 eV for the mean BH and zero-bias standard deviation, respectively, were obtained from this plot; then, a modified ln(I-o/T-2) - q(2)sigma(2)(s)/2k(2)T(2) versus q/kT plot gives (Phi(Bo)) over bar and A* as 0.992 eV and 108.228 A cm(-2) K-2, respectively. This value of A* is very close to the theoretical value of 112 A cm(-2) K-2 for n-type Si.